Span of spleen is associated with disability status in multiple sclerosis: a cross-sectional abdominopelvic ultrasonography study

Abstract

Characteristics of livers and spleens of people with multiple sclerosis (pwMS) could constitute good biomarkers of MS-related characteristics such as the disability status. To test the hypothesis "the gross anatomical features of livers and spleens, are not similar between pwMS with different disease characteristics" a cross-sectional study was conducted on pwMS seen at the Isfahan MS clinic, Iran, from February until December 2023. Definitive, otherwise-healthy, pwMS were enrolled after an initial laboratory evaluation. Presence/absence and grading of non-alcoholic fatty liver disease (NAFLD) and the span of spleen were determined by a radiologist using high-resolution abdominopelvic ultrasonography. 193 pwMS (160 women) were enrolled. Of whom, 143 (74.1%) were receiving first-line disease-modifying therapies (DMTs), 24 (12.4%) fingolimod, and 26 (13.5%) rituximab. The span of spleen was negatively associated with EDSS (adjusted β [SE] - 4.08 [1.52], p < 0.01), as well as 6 m-CDW (adjusted β [SE] - 6.94 [3.56], p = 0.05), unlike age, DMTs, and MS duration (all with p > 0.05). Receiver operating characteristic analysis showed, spleen span performs significant but poor in discrimination of EDSS > 1 from EDSS = 1 (area under curve [AUC] 0.62, SE 0.05, p < 0.01), yet, significant and fair in discrimination of presence from absence of 6 m-CDW (AUC 0.72, SE 0.06, p < 0.01). Other findings were unremarkable. Further longitudinal, prospective studies are warranted to confirm whether smaller spleens are predictive of higher disability accrual rate in pwMS. Particularly, findings require further validation in untreated/treatment-naïve pwMS, and ones with higher EDSS scores.

Figure 1

Study flow diagram. Abbreviation: APUS, abdominopelvic ultrasonography.

Figure 2

Status of NAFLD among participants as determined through APUS, stratified by EDSS score. Abbreviations: APUS, abdominopelvic ultrasonography; EDSS, expanded disability status scale; FLD, non-alcoholic fatty liver disease.

Figure 3

(a) scatter plot of span of spleen against EDSS score; the bold and hyphenated lines correspond to the regression and 95% confidence interval lines, respectively. (b) ROC curve of span of spleen for discrimination of EDSS = 1 from > 1. (c) scatter plot of span of spleen against presence or absence of 6 m-CDW in the prior year; the horizontal bold lines correspond to mean and standard deviation values and the vertical bold lines correspond to the values within one standard deviation of the mean. (d) ROC curve of span of spleen for discrimination between presence and absence of 6 m-CDW in the prior year. Abbreviations: mm, millimeters; EDSS, expanded disability status scale; SE, standard error; AUC, area under curve; CI, confidence interval; w/o, without; 6 m-CDW, 6-month confirmed disability worsening; **p < 0.01.